What is the treatment for amoebiasis?

Treatment of Amoebiasis

The treatment of amoebiasis requires a two-phase approach with tissue amebicides followed by luminal amebicides, with metronidazole or tinidazole as first-line therapy for invasive disease followed by paromomycin or diloxanide furoate to eliminate intestinal cysts. 1, 2, 3

Diagnosis Considerations

• Confirm diagnosis through:
  • Stool microscopy to identify Entamoeba histolytica trophozoites
  • Serological testing (indirect hemagglutination has >90% sensitivity for amoebic liver abscess)
  • Imaging studies (ultrasound or CT) for suspected liver abscess 1

Treatment Algorithm

1. Invasive Intestinal Amoebiasis or Amoebic Liver Abscess

First-line options:

• Metronidazole: 500 mg three times daily orally for 7-10 days (adults) 1, 3
  • Children: 30 mg/kg/day divided into three doses for 5-10 days 1
  • Efficacy: >90% cure rate 1

OR

• Tinidazole: 2 g once daily for 3 days (adults) 2, 4
  • Children >3 years: 50 mg/kg/day (up to 2g maximum) for 3 days 2
  • Advantages: Higher cure rate (90-96.5% vs 53-55.5% for metronidazole), fewer side effects, and shorter course 4, 5

2. Follow-up Treatment with Luminal Agent

After completing tissue amebicide treatment, ALL patients should receive a luminal amebicide to eliminate intestinal cysts and prevent relapse: 1

• Paromomycin: 30 mg/kg/day orally in 3 divided doses for 10 days 1, 6

OR

• Diloxanide furoate: 500 mg orally three times daily for 10 days 1

Special Clinical Scenarios

Amoebic Liver Abscess

• Start with metronidazole or tinidazole as above
• Ultrasound should be performed in all patients
• Consider CT scan if ultrasound is negative but clinical suspicion remains high
• Surgical or percutaneous drainage is rarely required and should only be considered if:
  • Diagnostic uncertainty persists
  • Symptoms persist after 4 days of treatment
  • Risk of imminent rupture exists (especially left-lobe abscesses that might rupture into pericardium) 1

Severe Disease/Unable to Take Oral Medication

• Use intravenous metronidazole
• Consider metronidazole retention enema (2g in 200ml normal saline) in patients who cannot take oral medications 7

Treatment Failure

• Most patients will respond to metronidazole within 72-96 hours
• If no improvement after initial therapy, consider:
  • Switching to alternative nitroimidazole
  • Extending treatment duration
  • Reevaluating diagnosis 1

Monitoring Response

• Clinical improvement should occur within 72-96 hours of starting therapy
• Monitor for resolution of fever, abdominal pain, and hepatomegaly
• For amoebic liver abscess, follow-up imaging may be warranted to ensure resolution 1

Precautions and Side Effects

• Metronidazole: Nausea, metallic taste, disulfiram-like reaction with alcohol
• Tinidazole: Generally better tolerated than metronidazole with fewer gastrointestinal side effects 4, 5
• Paromomycin: Minimal systemic absorption, generally well-tolerated

Prevention Strategies

• Improved sanitation and hygiene
• Safe food and water practices
• Consider treating asymptomatic household contacts if multiple cases occur in a household 1

Key Points to Remember

• Dual therapy (tissue amebicide followed by luminal agent) is essential for complete cure
• Tinidazole offers advantages of higher cure rates, fewer side effects, and shorter treatment duration compared to metronidazole
• Amoebic liver abscess rarely requires drainage unless there's risk of rupture or failure to respond to medical therapy
• All patients require luminal treatment even if stool microscopy is negative 1